Lacquer coatings

Acetone, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, ethyl acetate, and tetrahydrofuran are solvents for vinyhdene chloride polymers used in lacquer coatings methyl ethyl ketone and tetrahydrofuran are most extensively employed. Toluene is used as a diluent for either. Lacquers prepared at 10—20 wt % polymer sohds in a solvent blend of two parts ketone and one part toluene have a viscosity of 20—1000 mPa-s (=cP). Lacquers can be prepared from polymers of very high vinyhdene chloride content in tetrahydrofuran—toluene mixtures and stored at room temperature. Methyl ethyl ketone lacquers must be prepared and maintained at 60—70°C or the lacquer forms a sohd gel. It is critical in the manufacture of polymers for a lacquer apphcation to maintain a fairly narrow compositional distribution in the polymer to achieve good dissolution properties. 

Acetate propionate esters are nontoxic, exhibit excellent clarity and high tensile strength, and can be formulated into hot-melt dip coatings for food (168). Alternatively, they may be dissolved in volatile solvents and appHed to foods in the form of a lacquer coating (169). 

Uses. Cellulose nitrates with differing nitrogen contents have various appHcations (Table 3). The largest iadustrial use of CN is protective and decorative lacquer coatings. CN is soluble ia a variety of organic solvents and yields clear, tough films. CN is also compatible with many plasticizers and resias. 

Fig. 1. Lacquer-coated optical readout laser disk master. Plating by (a) electroless silver spray coating and by (b) vacuum evaporation. Scale bar, cm.

Lack-farbstoff, m. dye for lake making, -firms, m. lac varnish, lacquer lake varnish varnish. -fimislack, m. lac lake, -fiache, /. varnish surface lacquer coat, -harz, n. varnish gum, varnishing resin, esp. copal gum lac. -haut,/. lacquer (or varnish) film. 

Brotons, J.A., Oleaserrano, M.P., and Villalobos, M. et al. (1995). Xenoestrogens released from lacquer coatings in food cans. Environmental Health Perspectives 103, 608-612. 

Intermediates with wide civilian uses, for example, in the production of insecticides, pharmaceuticals, paints and lacquers, coating agents and lubricants etc. (e.g. phosgene, phosphorus oxygen chloride). 

EC FOOD CONTACT LEGISLATION AND HOW IN THE FUTURE IT MAY BE APPLIED TO LACQUER COATED FOOD AND BEVERAGE CANS... 

Pigment performance also includes fastness to transparent lacquer coatings ( silver lacquer ), that is, fastness to transparent enamels which are applied to metal deco prints to give them rub and scratch fastness. 

The fact that P.Y.127 recrystallizes only very slightly facilitates its dispersion in modern agitated ball mills. The pigment is easy to disperse and its heat stability parallels that of P.Y.13. Its fastness to clear lacquer coatings and to sterilization are excellent, which is why the pigment is suitable for metal deco printing. 

P.O.34 shows good solvent resistance to a number of organic solvents. Its prints are more stable in this respect than those made from P.O.13, which is also true for the standard DIN 16 524 solvent mixture (Sec. 1.6.2.1). In spite of these comparatively good fastness properties, P.O.34 may recrystallize in various printing inks, depending on the processing conditions. P.O.34 prints are fast to paraffin and dioctyl phthalate likewise, they tolerate clear lacquer coatings and may be sterilized. 

P.R.2 does not show perfect performance in special applications (Sec. 1.6.2.3) in prints, which is also true for a number of other members of this class. In this respect, P.R.2 is inferior to P.R.112. This may have a particular impact on marginal areas of pigment applicability. P.R.112 letterpress proof prints, for instance, tolerate mineral spirits and soap while P.R.2 prints only reach step 4 on the 5 step fastness scale. P.R.2 specimens are also sensitive to clear lacquer coatings and to sterilization. 

Pigment Red 8 affords clean, bluish shades of red. It is primarily used in the printing ink industry. P.R.8 exhibits high tinctorial strength and produces brilliant prints. Commercially available types with specific surface areas between about 50 and 60 m2/g afford transparent prints. P.R.8 is used in prints which require no particular solvent resistance. However, the pigment tolerates solvents much better than the yellower P.R.7 in this respect, P.R.8 matches the yellower, but more light-fast P.R.5. The prints are fast to soap but not entirely stable to butter and paraffin. P.R.8 is sensitive to clear lacquers coatings and to sterilization. It tolerates exposure to 140°C for 30 minutes. 

In applications where the pigment is fast enough to solvents to satisfy the requirements, it may also be used for offset, packaging gravure, and flexo printing inks. The resulting prints are soap, alkali, and acid resistant. They are not completely fast to paraffin and quite sensitive to butter and a number of other fats. P.R.14 prints are not fast to clear lacquer coatings and may not be sterilized. Heat stabil-... 

The prints tolerate white spirit, dibutyl phthalate, butter, soap, alkali, and acid. Moreover, they are also stable to clear lacquer coating their fastness to sterilization, on the other hand, exceeds that of P.R.57 1, but is not perfect. Where sterilization fastness is required, P.R.146 is superseded by P.R.185, a benzimidazolone pigment, which is its coloristically closest neighbor. 

P.R.210 is inferior to P.R.170 in various aspects of pigment performance. 1/3 SD and 1/25 SD letterpress proof prints, for instance, score 1/2 to 1 step less on the Blue Scale for lightfastness. In contrast to P.R.170, which is almost entirely fast to clear lacquer coatings and sterilization, P.R.210 is very sensitive in this respect. The two pigments behave similarly in print P.R.210 prints are equally fast to a number of organic solvents, paraffin, soap, alkali, and acid. They are also heat stable up to 200°C. 

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